Seat recline mechanism

ABSTRACT

A seat recline mechanism in which a fixed toothed sector connected to a seat back is engaged by a movable toothed locking member mounted on a mounting plate connected to a seat cushion. The teeth of the locking member are of substantially the same pitch as those of the fixed tooth sector and are positioned on an arc having a center of curvature outside the pivotal axes of the sector and the locking member.

I United States Patent 1191 1111 3,788,698 Perkins 1 1 Jan. 29, 1974 151 SEAT RECLINE MECHANISM 3,471,892 10/1969 Resag et a1. 16/146 xInventor: Norman w. Perkins, Benfleet 3,058,148 10/1962 Beierbach et al297/369 X England [73] Assignee: Ford Motor Company, Dearbom, PrimaryExaminer 4321511111 Nunbel'g Mi h Attorney, Agent, or Firm-Keith L.Zerschling; John J.

R th 1 22 Filed: May 8, 1972 O6 e [21] Appl. No.: 251,310

[57] ABSTRACT [30] Foreign Application Priority Data Nov. 26, 1971 GreatBritain 54,934/71 A seat recline mechanism in which a fixed toothedsector connected to a seat back is engaged by a mov- Cl 297/373, 1 7/367able toothed locking member mounted on a mounting [51] Int. Cl B60m1/02, E05d 11/10 plate connected to a seat cushion. The teeth of the[58] Field of Search 16/146, 139; locking member are of substantiallythe same pitch as 373 those of the fixed tooth sector and are positionedon an are having a center of curvature outside the pivotal [56]References Cited axes of the sector and the locking member.

UNITED STATES PATENTS 2,784,770 3/1957 Herr 297/367 5 Claims, 3 DrawingFigures /4 L (T jfl PATENTED JAN 2 9 1914 SEAT RECLINE MECHANISMBACKGROUND OF THE INVENTION Many seat recline mechanisms function byengagement of a fixed toothed sector by a movable toothed sector orlocking member. Each increment of tilting movement of the seat back is afunction of the pitch of the meshing teeth on the fixed and movablesegments. It has been found that the pitch of the teeth when located ona true pitch circle cannot be reduced below about 2 degrees withoutproducing incomplete meshing of the teeth of the fixed sector with theteeth of the movable locking member. The meshing conditions which occurwhen the pitch is reduced below 2 degrees can cause excessive wear andeventual failure of the mechanism.

It is an object of the present invention to provide a construction andarrangement in which teeth of less than 2 may be used thereby permittingfiner incremental adjustment of the angle of seat backrest inclination.

SUMMARY OF THE INVENTION According to the present invention the seatback recline mechanism has the following features: A toothed sector isfixed to a seat back mounting plate adapted to be connected to a seatback. A second or seat cushion mounting plate is adapted to be connectedto a seat cushion. A pivot means pivotally mounts the sector and theseat back mounting plate on the seat cushion mounting plate. A toothedlocking member is supported on a support means for pivotal and bodilyshiftable movement relative to the seat cushion mounting plate. Thetoothed locking member is manually engaged with the fixed sector and ispivotal about an axis substantially parallel to the pivotal axis of thesector. A releasing device is operable to move the pivotal axis of thesector and locking member apart to disengage the teeth of the sector andthe teeth of the locking member and permit angular adjustment of theseat back mounting plate and therefore the seat back relative to theseat cushion mounting plate. The teeth of the locking member are ofsubstantially the same pitch as those of the sector and are positionedon an are having a center of curvature outside the pivotal axes of thesector and the locking member.

DESCRIPTION OF THE DRAWING Further features and advantages of thepresent invention will be made more apparent as this descriptionproceeds, reference being had to the accompanying drawing, wherein:

FIG. 1 is a side elevation of a seat recline mechanism embodying theinvention;

FIG. 2 is a section on the line 2-2 of. FIG. 1; and

FIG. 3 is a section on the line 3-3 of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION An inner plate is fixed to a seatcushion frame (not shown). An outer plate 11, bolted to a seat backframe (not shown), is pivotally mounted on the inner plate 10 by a rivet12.

A sector or disc 13 of sintered material with fine teeth 14 (i.e., ofpitch about l.5 or less) at its periphery is welded to the outer plate11 concentrically with the rivet 12.

A locking member 15 is mounted on an eccentric hub 16 of a pivot 17pivotally mounted on the inner plate 10. The locking member 15 has teethof the same pitch as the teeth of the sector 13 formed on a concave edge18 having a radius of curvature greater than the radius of sector 13.Alternatively the toothed edge 18 may be straight or convex with acenter of curvature at the other side of the pivot 17.

A link 19 connects the outer end of rivet 12 and the outer part of pivot17 serves to hold the sector 13 and locking member 15 laterally aligned,and also helps to support the rivet 12 and pivot 17 against forcesgenerated at the point of contact of the sector and the locking memberwhich tend to force the rivet 12 and pivot 17 apart. In FIG. 1, part ofthe link 19 is cut away to expose the engaging portions of the lockingmember 15 and the sector 13.

A leaf spring 20 mounted at its ends to pins 21 on the inner platebiases the locking plate to a median position in which its concavetoothed edge 18 is aligned with the rivet 12 so that initiallyengagement of the toothed edge with the sector is always atsubstantially the middle of the toothed edge.

A lever 22 is screw-fastened to the outer end of the pivot 17 and theupper end of this lever is turned over to lie against a flat 23 on thehead of the pivot 17 to ensure that the lever 22 remains fast with thepivot 17.

The lower end of the lever 22 is connected by a cable 24 to the lowerend 30 of a handle 25 pivotally mounted at 26 to the seat cushion frame(not shown) at a location convenient to the hand of a person seated onthe seat.

A tension spring 31 connected between the lever 22 and the inner plate10 urges the pivot 17 in an anti clockwise direction and the angularposition of the eccentric hub 16 relative to the lever 22 is such thatanticlockwise movement of the pivot 17 brings the toothed locking member15 into engagement with the sector 13. It will be appreciated thatduring engagement the locking member may move angularly to align itselffor meshing engagement with the teeth of the sector 13.

In the engaged position forces applied to the seat either in the forwardor rearward direction tend to bring a portion of the locking member ofgreater distance from the pivot 17 into contact with the sector so thatthe seat back is prevented from moving appreciably and the contactpressure between toothed locking member 15 and sector 13 is increased.

The mechanism is disengaged for adjustment of the seat back position bypulling the upper end of the handle rearwardly. The lever 22 is thenmoved in a clockwise direction with the pivot 17 thereby withdrawing thelocking member 15 from the sector 13. The seat back is then free foradjustment between angular positions limited by engagement of a rivet 27fixed to the outer plate 1 l with stops 28 and 29 formed on the innerplate 10.

A simple pivot may be mounted at the other side of the seat or a similarrecline mechanism may be used. In the latter case levers 22 of the twomechanisms are connected by a cable for movement together when thehandle 25 is operated.

It is to be understood that the invention is not limited to the exactconstruction illustrated and described above, but that various changesand modifications may be made without departing from the spirit andscope of the invention as defined by the following claims.

I claim:

l. A seat recline mechanism having:

a toothed sector fixed to a seat back mounting plate adapted to beconnected to a seat back,

a seat cushion mounting plate adapted to be connected to a seat cushion,

pivot means pivotally mounting the sector and the seat back mountingplate on the seat cushion mounting plate,

a toothed locking member,

support means mounting the toothed locking mem ber for pivotal andbodily shiftable movement on the seat cushion mounting plate,

the toothed locking member being manually engaged with the sector andbeing pivotal about an axis substantially parallel to the pivotal axisof the sector,

and a releasing device operable to move the pivotal axes of the sectorand locking member apart to disengage the teeth of the sector and theteeth of the locking member and permit angular adjustment of the seatback mounting plate relative to the seat cushion mounting plate,

wherein the improvement comprises the teeth of the locking member beingof substantially the same pitch as those of the sector and positioned onan arc having a center of curvature outside the pivotal axes of thesector and the locking member.

2. A seat recline mechanism as claimed in claim 1, in

which:

a spring means urges the locking member towards an angular position inwhich its arcuate toothed portion is aligned for meshing engagement withthe sector teeth.

3. A seat recline mechanism as claimed in claim 2, in

which:

the locking member is mounted on an eccentric hub which is angularlymovable to bring the locking member into and out of engagement with thesector.

4. A seat recline mechanism having:

a toothed sector fixed to a seat back mounting plate adapted to beconnected to a seat back,

a seat cushion mounting plate adapted to be connected to a seat cushion,

pivot means pivotally mounting the sector and the seat back mountingplate on the seat cushion mounting plate,

a locking member having an arcuate toothed portion,

support means mounting the toothed locking member for pivotal and bodilyshiftable movement on the seat cushion mounting plate,

the toothed locking member being manually engaged with the sector andbeing pivotal about an axis substantially parallel to the pivotal axisof the sector,

and a releasing device operable to move the pivotal axes of the sectorand locking member in a direction to disengage the teeth of the lockingmember from the teeth of the sector to permit angular adjustment of theseat back mounting plate relative to the seat cushion mounting plate,

wherein the improvement comprises:

the arcuate toothed portion of the locking member being concave with aradius of curvature greater than the radius of the toothed sector.

5. A seat recline mechanism as claimed in claim 4, in

which:

the locking member is mounted on an eccentric hub which is angularlymovable to bring the locking member into and out of engagement with thesector.

1. A seat recline mechanism having: a toothed sector fixed to a seatback mounting plate adapted to be connected to a seat back, a seatcushion mounting plate adapted to be connected to a seat cushion, pivotmeans pivotally mounting the sector and the seat back mounting plate onthe seat cushion mounting plate, a toothed locking member, support meansmounting the toothed locking member for pivotal and bodily shiftablemovement on the seat cushion mounting plate, the toothed locking memberbeing manually engaged with the sector and being pivotal about an axissubstantially parallel to the pivotal axis of the sector, and areleasing device operable to move the pivotal axes of the sector andlocking member apart to disengage the teeth of the sector and the teethof the locking member and permit angular adjustment of the seat backmounting plate relative to the seat cushion mounting plate, wherein theimprovement comprises the teeth of the locking member being ofsubstantially the same pitch as those of the sector and positioned on anarc having a center of curvature outside the pivotal axes of the sectorand the locking member.
 2. A seat recline mechanism as claimed in claim1, in which: a spring means urges the locking member towards an angularposition in which its arcuate toothed portion is aligned for meshingengagement with the sector teeth.
 3. A seat recline mechanism as claimedin claim 2, in which: the locking member is mounted on an eccentric hubwhich is angularly movable to bring the locking member into and out ofengagement with the sector.
 4. A seat recline mechanism having: atoothed sector fixed to a seat back mounting plate adapted to beconnected to a seat back, a seat cushion mounting plate adapted to beconnected to a seat cushion, pivot means pivotally mounting the sectorand the seat back mounting plate on the seat cushion mounting plate, alocking member having an arcuate toothed portion, support means mountingthe toothed locking member for pivotal and bodily shiftable movement onthe seat cushion mounting plate, the toothed locking member beingmanually engaged with the sector and being pivotal about an axissubstantially parallel to the pivotal axis of the sector, and areleasing device operable to move the pivotal axes of the sector andlocking member in a direction to disengage the teeth of the lockingmember from the teeth of the sector to permit angular adjustment of theseat back mounting plate relative to the seat cushion mounting plate,wherein the improvement comprises: the arcuate toothed portion of thelocking member being concave with a radius of curvature greater than theradius of the toothed sector.
 5. A seat recline mechanism as claimed inclaim 4, in which: the locking member is mounted on an eccentric hubwhich is angularly movable to bring the locking member into and out ofengagement with the sector.